JPH0326802B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for surface modification of a micro color filter colored resin film for a color imaging device. More specifically, the present invention relates to a method for surface modification of a colored resin film of a micro color filter attached to a light receiving section of a color image pickup device including an image pickup tube and a solid-state image pickup device.

For example, in VTR cameras and the like, color image pickup tubes in which a light receiving section is provided with a micro color filter have been commonly used in order to extract color signals for color images. These color image pickup tubes are typified by, for example, types of image pickup tubes called sachicon, vidicon, and the like.

In other words, a color image pickup tube is a micro color image pickup tube in which minute color separation filter elements (colored resin films) such as red, green, and blue, or cyan, magenta, and yellow are combined in a mosaic or stripe pattern in the light receiving part of the image pickup tube. It consists of a structure with a filter attached.

On the other hand, recently, as a device to replace the image pickup tube,
For example, various solid-state image sensors such as CCD, BBD, and MOS have been developed, and color solid-state image sensors, which combine solid-state image sensors and micro color filters, have been developed with the main purpose of miniaturizing the VTR cameras mentioned above. Practical applications are being considered, and some have already been put into practical use.

A color solid-state image sensor has a photodetector on the surface of a light-receiving part, which consists of a flat imaging integrated circuit (IC) that integrates a photoelectric conversion element called a pixel and a scanning circuit.
A configuration with a micro color filter in which minute color separation filter elements (colored resin films) of red, green, and blue, or cyan, magenta, and yellow corresponding to each pixel are combined in a mosaic or stripe pattern. It is what it is.

Color solid-state image sensors are generally manufactured by a method called "bonding method" or "on-wafer method."

Among these methods, the bonding method involves forming a color separation filter element corresponding to each pixel of a solid-state image sensor on a transparent support such as glass to produce a micro color filter, and then bonding this to the surface of the solid-state image sensor. This is a method for making a color solid-state image sensor. Therefore, in this method, when adhering independently manufactured micro color filters to the surface of a solid-state image sensor, strict control is required so that each color separation filter element accurately corresponds to each pixel of the solid-state image sensor. operation is required.

On the other hand, the on-wafer method is a method in which a micro color filter is formed directly on a solid-state image sensor. Therefore, this on-wafer method has the advantage that it can be incorporated into the manufacturing process of a solid-state image sensor, and that it facilitates the manufacture of a color solid-state image sensor.

Note that the on-wafer method involves simultaneously manufacturing a large number of color solid-state image sensors by forming color separation filter elements corresponding to each pixel of each solid-state image sensor on a wafer on which a large number of solid-state image sensors are arranged. A single color solid-state image sensor is manufactured by cutting out a single solid-state image sensor (chip) from a wafer in which a large number of solid-state image sensors are arranged, and forming a color separation filter element on each chip. Although several methods (on-chip methods) are known, in this specification, any of these methods are included in the on-wafer method.

The following method is generally considered as a process for manufacturing a color imaging device.

A photocurable resin solution such as dichromate gelatin is coated on the light-receiving part of an imaging device (for example, the light-receiving part of an image pickup tube or solid-state image sensor) or on a transparent support such as glass attached to the light-receiving part. A photocurable resin layer is formed, and the surface of the photocurable resin layer is irradiated with light that has passed through an exposure pattern to generate mosaic-like or stripe-like cured portions on the resin layer.
Next, by washing this resin layer with an appropriate solvent, the uncured portions are dissolved and removed to obtain a mosaic or striped cured resin layer. Next, this cured resin layer is colored red, green, and blue. Color separation filter element (colored resin film) is dyed with a type of dye such as , cyan, magenta, or yellow.
Form I.

Next, a color contamination prevention layer is formed on the color separation filter element formed in this way, and a photocurable resin layer is further formed thereon in the same manner, and the light that has passed through another exposure pattern is applied to the surface of the layer. irradiation to produce another mosaic or stripe-like hardened portion in the resin layer. Then, in the same manner, the uncured resin portion is removed and the cured resin layer is dyed with another dye to form a color separation filter element. Further, if necessary, the operation for forming color separation filter elements is repeated to form a desired color separation filter group, and finally, a surface coating layer is formed to complete the formation of the micro color filter section.

Note that during or before or after each of the above operations, operations such as exposing the bonding pad part necessary for circuit formation may also be included.
Since these operations are not directly related to the present invention,
The explanation will be omitted.

In the process of forming a micro color filter section that has been commonly used in the past, as described above, a color stain prevention layer is formed on one type of color separation filter element, and then another color separation filter element of another dye type is formed. A method of forming is adopted. This is due to color contamination caused by the previously formed color separation filter element being further dyed in the dyeing process for forming the next color separation filter element.
and an intermediate layer formed for the purpose of preventing both color contamination (also called color mixing) caused by the dye of the previously formed color separation filter element bleeding into the next color separation filter element. It is. Therefore, the number of such intermediate layers is generally at least (number of color separation filter groups - 1)
You will need as many as

Among the above-mentioned imaging devices, solid-state imaging devices in particular integrate photoelectric conversion elements and scanning circuits, as mentioned above, and the degree of integration is, for example, several hundred thousand or more on a plane of about 10 mm in length and width. It is so high that it includes over one million photoelectric conversion elements (pixels). Therefore, in the processing of such ultra-precision parts, it is extremely important to reduce the number of processing steps even by one, because reducing the number of processing steps directly leads to an improvement in the yield of the final product, the color solid-state image sensor. It is desirable to omit, if possible, the formation process of layers that are not related to the performance of the formed micro color filter itself, such as the above-mentioned color stain prevention layer.

Based on the above-mentioned background, after the formation of each color separation filter element, the surface layer of the color separation filter element is modified so that the dye solution remains stable even when it is later contacted with another dye solution. by preventing the dye from penetrating into the interior of the color separation filter element, and by preventing the dye from the previously formed color separation filter element from bleeding out and contaminating the color of the next formed color separation filter element. It has also been proposed to omit the provision of a color stain prevention layer.

For example, Japanese Patent Application Laid-Open No. 55-25067 discloses that a colored resin film provided on a substrate (support) such as a transparent glass substrate is treated with an aqueous solution of tannic acid and acetic acid and an aqueous solution of antimonyl potassium tartrate. Discloses a method for surface modification. This method is effective as a treatment method for preventing color contamination of colored resin films, but according to the study of the present inventor, reticleation and It has been found that there is a tendency for fine crepe-like wrinkles called so-called crepe-like wrinkles to occur, and that this reticulation is particularly noticeable when a gelatin-based photocurable resin is used as the photocurable resin. A micro color filter made of a colored resin film in which such retickling occurs is not preferred because it causes deterioration in performance such as a decrease in the amount of transmitted light and variation in the amount of transmitted light, which deteriorates the quality of the color imaging device. do not have.

Therefore, the present invention provides a method for forming a micro color filter on a light receiving section of a color imaging device or on a transparent support attached to a light receiving section of a color imaging device. By applying a color stain prevention modification treatment to the surface of the color separation filter element (color separation filter element) that does not cause undesirable phenomena such as reticulation, there is no adverse effect on the light that passes through the color separation filter. The object of the present invention is to provide a technique that makes it possible to omit a color stain prevention layer.

The present invention provides a method for coating the surface of a colored resin film formed using a photocurable resin made of dichromic acid or a proteinaceous material containing chromic acid on a light receiving section of an imaging device or a transparent support attached to the light receiving section. Hardening treatment is performed by treating with a chromium salt hardener aqueous solution, followed by heat treatment at a temperature of 130 to 200°C, and then sequentially using an acidic aqueous solution containing tannic acid and an alkali metal salt aqueous solution of antimonyl tartrate. This method consists of a method for surface modification of a colored resin film of a micro color filter for a color imaging device, which is characterized in that the surface modification is carried out using a method of surface modification.

Next, the present invention will be explained in detail.

The imaging device used in the present invention includes, for example, an imaging tube and a solid-state imaging device.

The type and structure of the image pickup tube are not particularly limited, and various types of image pickup tubes such as the known vidicon, sachicon, plumbicon, and carnicon can be used.

The solid-state image sensor is not particularly limited in its type, structure, etc., and various solid-state image sensors such as well-known CCD, BBD, and MOS can be used, for example.

However, if the present invention is used in a method in which the step of attaching a micro color filter to the light receiving section of a solid-state image sensor is performed by an on-wafer method, the solid-state image sensor may be contaminated with impurities, such as dirt or dust, during that step. It is necessary to use a solid-state imaging device provided with a transparent protective layer to prevent contamination by foreign ions, especially alkali metal ions. This protective layer is formed from a transparent organic or inorganic material, such as phosphosilicate glass. However, as long as the above purpose of installing the protective layer is achieved, there are no particular limitations on the material, thickness, or installation method. Furthermore, if the surface of the protective layer is not sufficiently smooth or for other reasons, another layer such as a smooth layer made of a material such as a transparent resin may be further provided on the protective layer. In such cases, the colored resin film is formed on the smooth layer.

When carrying out the present invention, the colored resin film is
For example, it is formed by the following method.

First, on the light receiving part of the image pickup tube, on the protective layer of the light receiving part of the solid-state image sensor (if there is another layer such as a smooth layer on the protective layer, on the top layer thereof),
Alternatively, a photocurable resin solution is applied to a transparent support (such as glass) attached to a light receiving section of an image pickup tube or a solid-state image sensor to form a photocurable resin. As the photocurable resin, dichromic acid or a proteinaceous material containing chromic acid, such as dichromate gelatin, chromate gelatin, dichromate casein, dichromate glue, etc., is used. However, the surface modification method of the present invention is particularly useful when the photocurable resin is a gelatin-based photocurable resin.

Next, the surface of the photocurable resin layer is irradiated with light through a mosaic or stripe-like exposure pattern to generate a mosaic or stripe-like cured portion on the resin layer corresponding to the exposure pattern. . Then, remove this resin layer with a suitable solvent.
For example, when dichromate gelatin is used as the photocurable resin, uncured portions are dissolved and removed by washing with hot water to obtain a mosaic or striped cured resin layer.

The cured resin layer formed as described above is then dyed with one of red, green, blue, cyan, magenta, or yellow dyes to form a colored resin film that functions as a color separation filter element. obtain. As dyes used for this dyeing, various acid dyes, direct dyes, reactive dyes, etc. are already known, and in the present invention, dyes can be arbitrarily selected from among these known dyes or dyes having equivalent properties. Any dye of your choice can be used.

In the present invention, the surface of the colored resin film formed as described above is first subjected to a hardening treatment. In this hardening process, the surface of the formed colored resin film is treated with an aqueous solution of a chromium salt hardener such as chrome alum or chromium acetate, and then heated at a temperature of 130 to 200°C, usually 20°C. This can be carried out using a heating treatment method for about a minute to an hour.

The colored resin film subjected to the hardening treatment is then subjected to surface modification using an acidic aqueous solution containing tannic acid and an aqueous alkali metal tartrate solution in this order.

As the tannic acid-containing acidic aqueous solution, it is generally preferable to use a tannic acid-containing acidic aqueous solution made acidic with acetic acid. In addition, the concentration of tannic acid in the aqueous solution ranges from 0.05 to 1.0% by weight,
The concentration of acid such as acetic acid is preferably selected from the range of 0.01 to 2.0% by weight. When a hardened colored resin film is treated with an acidic aqueous solution containing tannic acid, the treatment is generally carried out while maintaining the aqueous solution at a temperature in the range of 10 to 80°C, preferably in the range of room temperature to 60°C.

As the aqueous alkali metal antimol tartrate solution, it is preferable to use an aqueous solution of potassium antimonyl tartrate, which is generally called tartarite. Further, the concentration of the alkali metal antimonyl tartrate in the aqueous solution is preferably selected from the range of 0.02 to 5.0% by weight. The treatment temperature is selected from a range of 10 to 80°C, preferably from room temperature to 60°C.

In addition, between each process described so far, a washing process, a drying process, or a washing/washing process may be performed as necessary.
A drying step may also be included.

The colored resin film whose surface has been modified through the treatment steps described above may be subjected to a similar process starting from the step of applying a photocurable resin solution to form a photocurable resin layer, if necessary. Colored resin film formation and surface modification treatment can be repeated,
Next, a surface protective layer is provided to complete the application of the color filter layer.

The colored resin film (color separation filter element) treated by the surface modification method of the present invention has sufficient color contamination for practical use without causing undesirable phenomena such as reticleation on the surface after treatment. Demonstrates prevention function. Therefore, there is an advantage that the intermediate layer for preventing color contamination of the micro color filter can be omitted without any adverse effect on the light transmitted through the color separation filter element, and it can be used in a method for manufacturing a color imaging device. In particular, it can be advantageously used in a method of manufacturing a color solid-state sensor using an on-wafer method.

Next, Examples and Comparative Examples of the present invention will be shown.

[Example 1] A 0.7 micron thick layer was placed on the smoothing layer of a CCD type solid-state image sensor (the surface of which is provided with a protective layer made of phosphosilicate glass and a smoothing layer made of a transparent organic polymer compound). A dichromate gelatin photocurable resin layer was provided, and a mask (exposure pattern) consisting of a mosaic pattern was placed thereon to perform contact exposure. Next, the exposed resin layer was washed with hot water to elute and remove the uncured portions of the resin, leaving a cured resin layer consisting of mosaic-like convex portions.

This cured resin layer was dyed with a yellow dye (Sminol Milling Yellow MR: manufactured by Sumitomo Chemical Co., Ltd.) to prepare a colored resin film.

This colored resin film was first treated with a chromium alum hardening solution (an aqueous solution containing 2% by weight of chrome alum and 1% by weight of anhydrous sodium sulfite, adjusted to pH 4 with acetic acid) at 40°C for 3 minutes. Then, after washing with water, the film was hardened by heating at 170°C for 30 minutes.

The hardened colored resin film was treated with an acetic acid tannic acid aqueous solution (an aqueous solution containing 0.2% by weight of tannic acid and acetic acid 1% by weight) at 40°C for 1 minute, then washed with water, dried, and treated with antimony tartrate at 40°C. The colored resin film was treated with a dipotassium aqueous solution (an aqueous solution containing 0.5% by weight of potassium antimonyl tartrate and 0.25% by weight of acetic acid) for 1 minute to perform a color stain prevention modification treatment.

When the surface condition of the colored resin film subjected to the above surface modification treatment was observed under a microscope, it was confirmed that no retickling occurred at all.

[Example 2] The colored resin film prepared by the method described in Example 1 was hardened by the method described in Example 1, and then the temperature of the acetic acid tannic acid aqueous solution was changed to 20 ° C. The same color stain prevention modification treatment as in Example 1 was carried out, except that the temperature of the antimonyl potassium tartrate aqueous solution was also changed to 20°C.

When the surface condition of the colored resin film subjected to the above surface modification treatment was observed under a microscope, it was confirmed that no retickling occurred at all.

[Example 3] The colored resin film prepared by the method described in Example 1 was subjected to the same hardening treatment as in Example 1 except that the heating temperature was changed to 150°C, and then,
Color stain prevention modification treatment was carried out by the method described in Example 2.

When the surface condition of the colored resin film subjected to the above surface modification treatment was observed under a microscope, it was confirmed that no retickling occurred at all.

[Example 4] The colored resin film prepared by the method described in Example 1 was hardened by the method described in Example 1, and then the antimonyl potassium tartrate content of the antimonyl potassium tartrate aqueous solution was The same color stain prevention modification treatment as in Example 1 was carried out except that the amount was changed to 0.25% by weight.

When the surface condition of the colored resin film subjected to the above surface modification treatment was observed under a microscope, it was confirmed that no retickling occurred at all.

[Comparative Example 1] The colored resin film prepared by the method described in Example 1 was directly subjected to color stain prevention modification treatment by the method described in Example 1 without performing a hardening treatment.

When the surface condition of the colored resin film subjected to the above surface modification treatment was observed under a microscope, the occurrence of reticle retardation was observed to be significant.

[Comparative Example 2] The colored resin film prepared by the method described in Example 1 was directly subjected to a color stain prevention modification treatment without being subjected to a hardening treatment. This surface modification treatment was carried out in accordance with the method described in Example 1, except that the treatment time with the acetic acid tannic acid aqueous solution and the treatment time with the antimonyl potassium tartrate aqueous solution were both changed to 30 seconds.

When the surface condition of the colored resin film subjected to the above surface modification treatment was observed under a microscope, the occurrence of reticle retardation was observed to be significant.

[Comparative Example 3] The colored resin film prepared by the method described in Example 1 was directly subjected to a color stain prevention modification treatment without being subjected to a hardening treatment. This surface modification treatment was carried out in Example 1, except that the treatment time with the acetic acid tannic acid aqueous solution and the treatment temperature with the antimonyl potassium tartrate aqueous solution were both changed to 30°C.
The method described was followed.

When the surface condition of the colored resin film subjected to the above surface modification treatment was observed under a microscope, the occurrence of reticle retardation was observed to be significant.

Claims (1)

[Scope of Claims] 1. A colored resin film formed using a photocurable resin made of dichromic acid or a proteinaceous material containing chromic acid on a light-receiving section of an imaging device or a transparent support attached to the light-receiving section. The surface of the film is treated with an aqueous solution of a chromium salt-based hardener, and then hardened by heat treatment at a temperature of 130 to 200°C, followed by an acid aqueous solution containing tannic acid and an aqueous alkali metal salt antimony tartrate solution. 1. A method for surface modification of a colored resin film of a micro color filter for a color imaging device, characterized in that the surface is modified using sequentially the following methods. 2. The method of surface modification of a colored resin film according to claim 1, wherein the hardener aqueous solution is a chromium alum aqueous solution.